1. Field of the Invention
The present invention relates to container closures and, more particularly, to a tamper evident container closure construction of the type providing indication of previous opening and possible tampering with a container's contents.
2. Description of the Prior Art
In recent years there has been an emphasis on ensuring that the dispensing (neck) openings of containers are provided with tamper evident closures and, more particularly, closures that are resistant to opening and which, when opened, provide an indication of such opening. A known type of tamper evident closure construction includes multi-part cap closures whereby an overcap, which encloses a container dispenser opening, is connected by way of tamper evident frangible or snap-fit connections to a base cap that further incorporates a second tamper evident feature. The overcap requires removal prior to a dispensing operation and may be discarded or, if possible, replaced on the dispenser. The base cap is a protective cap which functions to provide an indication of tampering when an attempt has been made to remove the base cap so as to refill or change the contents of the container.
U.S. Pat. No. 4,546,893 shows one construction of a multi-part cap closure including an overcap and a base portion, the latter being snapped into position on the container and held permanently thereon by means of cooperative retainer shoulders. When the overcap is initially turned or otherwise disturbed, frangible webs, connecting it to the base portion, break and their resilience causes a tamper evident ring to shift laterally attracting attention of one handling the container and providing a warning of tampering. The base portion is itself of tamper evident construction since it provides an indication of tampering therewith due to its easily deformable nature. Thus, any attempt to remove the base portion and overcap combination, tampering with the container contents and then re-attaching the overcap and base portion combination, would be readily detected. This is because, even though the overcap remains intact with the base portion, the prying off of the base portion would necessarily have caused it to become deformed. While the tamper evident feature of the base portion is useful, the base portion itself is not in any way uniquely constructed to seal and secure the dispenser to the neck of the container.
U.S. Pat. No. 4,709,823 discloses yet another construction of a tamper evident closure for use in connection with pull-to-open push-to-close (push-pull) type dispensing caps and the like. When an overcap is assembled to a base portion by frangible connections, access to the push-pull device is blocked. The overcap and base portion combination is restrained against removal by the abutment of the top surface areas of a plurality of axially extending and radially inwardly projecting ribs, formed on the base portion, against a radially outwardly extending bead or lip on the push-pull closure. Rotation of the push-pull closure in the direction of removal of same together with the overcap and base portion is prevented by the anti-rotation engagement of radially outwardly extending projections formed on the container neck with the axially extending ribs on the base portion. Thus, the container cannot be opened and the contents thereof cannot be tampered with or dispensed. In order to provide access to the push-pull dispensing valve, the overcap must be severed by breaking of the frangible connections. When this happens, the overcap is permanently disengaged. However, the base portion remains in position on the container providing an indication of tampering. Once the base portion is separated from the overcap, it can be slid downwardly along the neck of the container toward the shoulders of the bottle. Depending on the length of the neck, the base portion may be displaced sufficiently from a threaded portion of the push-pull closure to permit its removal, the contents tampered with and then reassembled. There is no tamper evident indication available other than that provided by the initial disengagement of the overcap from the base portion. The base portion of the tamper evident container closure and the threaded portion of the push-pull closure are arranged as cooperating skirts around the container neck. While this two piece skirted construction is highly effective, unfortunately, it is also expensive and difficult to manufacture.
Yet another construction is illustrated in U.S. Pat. No. 4.764,035 involving dispensers of the pump and aerosol varieties. A protective overcap covering the dispenser's actuator is connected to a base closure cap of the dispenser actuator, which closure cap is employed for mounting the dispenser actuator on a liquid container. Circumferentially spaced-apart stops are provided between the overcap and the closure cap permitting limited turning movement of the overcap prior to separation from the closure cap. Cooperating flanges, acting between the overcap and closure cap, retain the overcap in place by snap-fitting engagement. Frangible connections above the cooperating flanges provide for permanent separation of an upper portion of the overcap permitting access to the dispenser actuator. The closure cap is also provided with a tamper evident ring that breaks away from the closure cap upon turning same in the direction of opening. A two-piece, non-integral construction of closure cap and overcap, as in the above-described container closure, results in unnecessary increases in cost of assembly and manufacture. Also, the base of the pump dispenser actuator is dimensioned to be received by the closure cap and does not mate directly into the container discharge orifice. This is important because conventional push-pull dispenser caps are generally provided with an outer base skirt which is internally threaded to facilitate screwing the same onto the container neck. Since the closure cap of the '035 patent is threaded directly onto the container neck, a push-pull type dispenser cap could not be substituted for the pump-type dispenser actuator of the disclosed embodiment.
It would therefore be an advance in the art to provide an improved, unitary, one-piece, tamper evident cap closure for use with a wide variety of dispenser caps, particularly push-pull type dispenser caps, which tamper evident closure and dispenser cap combination overcomes the shortcomings of conventional constructions.